Controllers have long been used to regulate the motion of airborne objects on a tether. Kites have been classically tethered on a single line which could be pulled on to effect the kites interaction with the air currents. Model airplanes have frequently been controlled by the use of a dual line control system. The lines are connected to a handle in a spaced apart relationship and by pivoting the handle the effective lengths of the two lines can be changed, these changes being translated into changes in the inclination of the airplane's elevator and inducing a change in the flight path of the airplane.
Stunt kites employing multiple lines have been used to change the inclination of kites with respect to the wind direction causing the kites to move responsive to those changes. The lines have frequently been connected to a handle in a spaced apart relationship and by pivoting the handle the effective lengths of the two lines are changed tilting the kite with respect to its inclination to the wind.
One of the difficulties with multiple line control systems has been the difficulty in providing for a change in distance between the operator and the kite or airplane being controlled.
Dual spools have been employed to let out or take in additional line. However, these devices have not been effective since they are winding and unwinding against a differential tension resulting in unequal lengths of line being let out or taken in and destabilization of the flight path of the airplane or kite being controlled. This problem has in part been overcome by passing the two lines through an anchor ring between the control handle and the kite or airplane being controlled thereby. This provides a method for uniformly changing the length of the lines between the anchor and the kite or airplane by moving away from the anchor. This technique of flying finds limited application since the control becomes indirect and thus more difficult to introduce the desired control changes.
Thus there is a need for a direct control system that will allow lines to be uniformly released or taken in while a kite or plane is in flight.